In ophthalmic surgery, and in particular in vitreo-retinal surgery, it is desirable to use a wide-angle surgical microscope system to view as large a portion of the retina as possible. Wide-angle objective lenses for such microscopic systems exist, but they require a wider illumination field than that provided by the cone of illumination of a typical fiber-optic probe. As a result, various technologies have been developed to increase the beam spreading of the relatively incoherent light provided by a fiber-optic illuminator. These known wide-angle illuminators can thus illuminate a larger portion of the retina as required by current wide-angle surgical microscope systems. Currently existing wide-angle illuminators, however, display several disadvantages.
One disadvantage of prior art small gauge, wide-angle illuminators for ophthalmic surgery is the lack of rigidity of the cannula that is inserted into and extends into the eye. In ophthalmic surgery, such as vitreo-retinal surgery, the primary function of an illumination probe is to provide illumination for the surgical area. A secondary function is to manipulate portions of the eye near the surgical area to provide an unobstructed view and to allow access to a surgical area, such as the periphery of the retina. However, to manipulate tissue within the eye, the illuminator cannula must have a certain rigidity. Due to their larger diameter, the cannulas of 20 gauge devices provide adequate rigidity for surgeons to manipulate tissue in the eye. However, 25 gauge devices have a smaller diameter cannula (e.g., 0.0205 inches) with thin walls resulting in a much more flexible probe (cannula) than a same length 20 gauge cannula. Prior art small-gauge illuminaters (<20 gauge) do not, therefore, provide sufficient rigidity to effectively manipulate tissue in the eye in the manner of larger gauge illuminators.
Therefore, a need exists for a small-gauge wide-angle illuminator for illumination of a surgical field that can reduce or eliminate the problem of lack of rigidity for manipulating eye tissue associated with prior art small gauge, wide-angle illuminators.